Becoming Japan’s first Grand Slam singles champion is Naomi Osaka’s number one priority but finding a friend or two is a close second.

The charismatic 20-year-old was part of a history-making double act at the US Open on Monday when she and Kei Nishikori became the first Japanese players to make the last-eight at the same Slam since Wimbledon in 1995.

But after seeing off Aryna Sabalenka of Belarus 6-3, 2-6, 6-4 to become the first Japanese woman in the US Open quarter-finals since Shinobu Asagoe in 2004, Osaka hoped that her social life might now pick up.

“What friends?” she responded when asked if she will celebrate her emotional victory with friends in New York, the city where her Haitian-born father attended university.

“Oh, my God, I literally only have, like, one friend that I’m actually completely myself with. I feel bad for her sometimes.

“And then the other person is my sister. I don’t really count that as a friend.

“I guess I tell jokes a lot, but I’m not really that sure because sometimes they don’t laugh and they just stare at me like I said something insulting.”

On Monday, Osaka came back from a break down in the final set to take the tie on a fourth match point when Sabalenka served up an eighth double fault.

“I would never have forgiven myself if I had lost that match today,” said a tearful Osaka.

“When I was a break down in the final set I thought I would even break a leg if needed so I could get to every ball.”

Osaka, seeded 20 at the US Open, has been knocking on the door of the majors for the last three years.

Her previous two trips to New York had ended in third round losses to Madison Keys last year and Kaia Kanepi in 2016.

In both matches she had taken the first set.

At the Australian Open in January, she went to the fourth round where it took world number one Simona Halep to stop her.

She is enjoying a breakout season, winning the prestigious Indian Wells title in March before beating Serena Williams in the first round in Miami.

“Every time I play a Grand Slam, people ask me am I going to go further than the third round,” she said.

“Then in Australia I went to the fourth round, then people were like, are you going to go further than that or is that where you’re going to stop?

“I’ve always dreamed of playing here and going to the quarter-finals and further. So I’m just glad I could do one of my goals.”

Next up for Osaka is a clash against Ukraine’s 36th-ranked — and fellow Grand Slam quarter-final debutant — Lesia Tsurenko.

The 29-year-old had been on the brink of collapse due to heat exhaustion before seeing off Czech teenager Marketa Vondrousova 6-7 (3/7), 7-5, 6-2.